What is mast cell activation syndrome (MCAS)?

Veröffentlicht am: October 09, 2024
Dr. med. Wolfgang Bachmann
Dr. med. Wolfgang Bachmann

General practitioner

What is mast cell activation syndrome (MCAS)?

Mast cell activation syndrome (MCAS) means that mast cells increase the release of messenger substances, which can lead to various symptoms. Unfortunately, diagnosing that the person affected has MCAS is very time-consuming and is often only possible by ruling out other diseases based on the symptoms.

 

➤  It is estimated that 7-15% suffer from this disease, but the diagnosis is often missing.

 

But what exactly are mast cells? How does mast cell activation syndrome manifest itself? You can find out more about this topic in this guide.

 

Contents

What are mast cells?

➤  Did you know that mast cells (mastocytes) are the most important pillars of the immune system in the human body?

If you look at these cells under the microscope, you can see that, unlike other cells, they contain small spheres. These are there to store messenger substances (chemical signaling substances).

In turn, messenger substances are needed to initiate and strengthen an appropriate immune system response upon contact with viruses, bacteria, parasites and allergens. These cells and the messenger substances they transport are also involved in wound healing and nerve protection.

Mast cells are distributed in all organs and tissues. They are mainly found along the outer borders (intestines, skin, mucous membranes), along blood vessels and nerves. The cells are formed from stem cells (precursor cells) in the bone marrow, from where they migrate through the body tissue until they settle in one place and perform their function.

What is mast cell activation syndrome?

Mast cell activation syndrome (MCAS) occurs when mast cells no longer only trigger an immune response to allergens, viruses or similar. Instead, they are permanently active and the messenger substances mentioned are increasingly released. This means that the cells are "combative" even without inflammation, thereby increasing the histamine concentration in the body, for example.

Histamine plays an important role in the sleep-wake rhythm and also influences our appetite. However, too much of this messenger substance in the body can cause allergic skin reactions. Heparin is another messenger substance that is responsible for the dilation of blood vessels and blood thinning. Due to a high release of heparin, patients suffering from MCAS tend to bleed more heavily after injuries, during an operation or during their menstrual phase, for example.

Molecular pharmacologist Professor Dr. Gerhard J. Molderings from the Institute of Pharmacology and Toxicology at the University Hospital Bonn has been researching mast cell activation syndrome for several years. He suspects that many symptoms that could not previously be assigned to a disease are indications of MCAS.

What are the symptoms of MCAS?

The symptoms can vary depending on which organ is affected by the altered mast cells. Symptoms often resemble a chronic inflammatory disease, a cold and sometimes symptoms similar to food poisoning can also occur.

Other symptoms:

  • Dizziness
  • Concentration disorders
  • Insomnia and panic attacks
  • Allergic reactions such as itchy patches, wheals, redness
  • Blisters on the skin
  • Problems with the gastrointestinal tract (indigestion, cramps and pain)
  • Increased bleeding during operations
  • Menstrual cramps and increased bleeding
  • Bone pain
  • Anaphylactic reactions

What forms of primary mast cell activation syndrome are there?

1. skin mastocytosis

In this form of the disease, there are only good accumulations of mast cells, which are limited to the skin and do not affect the bone marrow or other organs. Reddish-brown pigment spots, some of which form blisters on the skin, can be seen. If these are rubbed, the release of histamines from the mast cells is increased, which can lead to swelling.

 

➤ The disease usually occurs in childhood and often heals by puberty.

2. systematic mastocytosis (SM)

Systematic mastocytosis comprises several diseases, all of which show an abnormal accumulation of mast cells in an internal organ. Several organs can be affected by an increased number of cells.

3. mast cell leukemia (MCL)

This form occurs less frequently and develops when malignant mast cell mutations multiply rapidly and unchecked. It is a form of cancer but without a tumor settling in one place. This means that in this form of cancer, a malignantly mutated cell multiplies in the blood and spreads throughout the body.

4 Systematic mast cell overactivity disorder

In this disease, the focus is not on cell division, but rather on the decrease in mast cell apoptosis. Apoptosis is a form of programmed cell death. This means that in this form of the disease, the cells become more long-lived, resulting in a slow increase in the number of mast cells in the body. This increases the concentration of messenger substances, which in turn can cause various symptoms.

How is MCAS diagnosed?

A thorough medical history is taken using a questionnaire, which can help to classify the symptoms. A physical examination, during which skin changes can be detected, is followed by a sonography of organs such as the liver and spleen. In addition, a gastroscopy and colonoscopy are performed, during which the biopsies are tested for various antibodies and the mast cells are counted. Some mast cell mediators can be detected by laboratory tests, although the number of clinics performing these tests is very small.

The diagnosis of MCAS is very difficult and elevated values can often not be detected. The diagnosis is then made by excluding other diseases.

How is MCAS treated?

  • Foods rich in histamine should be avoided. These include, for example, citrus fruits, strawberries, pulses, cheese and smoked products (ham, salami, smoked fish)
  • The amount of histamine absorbed can be reduced by also avoiding alcohol. Alcohol can generally promote MCAS. Red wine in particular contains high amounts of histamine, which promotes the disease.
  • Triggering factors that are already known should be avoided (e.g. allergies)
  • Combination of H1 and H2 antihistamines as basic therapy
  • Depending on tolerance, mast cell stabilizers such as cromoglycic acid and quercetin can be administered gradually
  • Vitamin C, up to a maximum of 750 mg daily, can help to inhibit mast cell degranulation
 

Sources (in German):

Brockow, K.(2013). Mastzellaktivierungssyndrome. Hautarzt 64, 102–106. doi: 10.1007/s00105-012-2452-6

Delves J. P, Mastozytose. (2019). Online unter: https://www.msdmanuals.com/de/heim/immunst%C3%B6rungen/allergische-reaktionen-und-andere-hypersensitivit%C3%A4tsst%C3%B6rungen/mastozytose

Molderings G. J., Homann J., Brettner S., Raithel M., Frieling T. (2014). Systemische Mastzellaktivierungserkrankung: Ein praxisorientierter Leitfaden zu Diagnostik und Therapie [Mast cell activation disease: a concise practical guide for diagnostic workup and therapeutic options]. Dtsch Med Wochenschr. 139(30):1523-1538. doi:10.1055/s-0034-1370055

Sturm, Karina. “Das Mastzellaktivierungssyndrom. Eine Volkskrankheit?” Das Mastzellaktivierungssyndrom (2017).

Tischler D., Jossé U. S. (2018). “Mastzellen-Aktivierungssyndrom: Spielt Ernährung Eine Rolle?” Online unter: www.mein-allergie-portal.com/mastozytose/1547-mastzellenaktivierungssyndrom-spielt-ernaehrung-eine-rolle/all-pages.html.

 

Sources (in English):

Akin C., Valent P., Metcalfe D.D. (2010). Mast cell activation syndrome: Proposed diagnostic criteria. J Allergy Clin Immunol. 126(6):1099-104.e4. doi:10.1016/j.jaci.2010.08.035

Bains S.N., Hsieh F.H. (2010). Current approaches to the diagnosis and treatment of systemic mastocytosis. Ann Allergy Asthma Immunol. 2010;104(1):1-41. doi:10.1016/j.anai.2009.11.006

Homann J., Kolck U.W., Ehnes A., Frieling T., Raithel M., Molderings G.J. (2010). Die systemische Mastozytose--Standortbestimmung einer internistischen Erkrankung. Med Klin (Munich). 2010;105(8):544-553. doi:10.1007/s00063-010-1093-8

Molderings, G. J. et al. (2011). “Mast cell activation disease: a concise practical guide for diagnostic workup and therapeutic options.” Journal of hematology & oncology vol. 4 10. 22 Mar. 2011, doi:10.1186/1756-8722-4-10

Picard M., Giavina-Bianchi P., Mezzano V., Castells M.(2013). Expanding spectrum of mast cell activation disorders: monoclonal and idiopathic mast cell activation syndromes. Clin Ther. 35(5):548-562. doi:10.1016/j.clinthera.2013.04.001

Valent P., Akin C., Arock M., et al. (2012). Definitions, criteria and global classification of mast cell disorders with special reference to mast cell activation syndromes: a consensus proposal. Int Arch Allergy Immunol. 157(3):215-225. doi:10.1159/000328760